- Correspondence to Professor Ping Zhong, Department of AIDS and STD, Shanghai Municipal Center for Disease Control and Prevention, Shanghai Municipal Institutes for Preventive Medicine, 1380 Zhongshan Road (W), Shanghai 200336, China; and Pingmin Wei, Teaching and Research Office of Epidemiology and Health Statistics, School of Public Health, Southeast University, 87 Dingjiaqiao Road (W), Nanjing 210009, China;
- Received December 26, 2016
- Revised May 10, 2017
- Accepted June 10, 2017
- First published August 7, 2017.
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